a. Field
The present invention relates to improvements in inhalers and in particular to improvements in Breath Actuated Inhalers (BAIs).
b. Description of Related Art
A BAI is an inhaler type which does not dispense medication until the flow therein is sufficient. This flow is important to obtain the desired result of the medication.
In the situation where it is desired that the medication reaches the lungs, for example, the flow or flow rate and the droplet/powder size will determine whether the mediation impacts the throat of the person or whether it reaches the lungs. They will also determine whether medication having reached the lungs will impact the lungs and stay there or be exhaled again.
The droplet/powder size normally is controlled by the medication/valve/canister/nozzle and may normally not be altered by the user. The flow, however, is just as important, which is the reason for the use of BAIs.
Standard BAIs have a lockable spring which is loaded by the user and which is used for compressing the canister at a later point in time, where after the user needs not provide additional force and may concentrate only on inhaling sufficiently in order to receive the medication.
However such loaded springs may be loaded over extended periods of time, whereby the material receiving and restraining the force/load may experience material creep or deformation, which will lead to dimension changes to the dispenser. Such dimension changes may result in an insufficient compression of the canister or other disadvantages in the medication providing.
Another problem may be seen when compressing a canister for a prolonged period of time. Canisters are not guaranteed tight when compressed, so a leakage of medication or propellant may be experienced, which is a major problem due to the amount of medication and the number of doses no longer being exact.
In addition, as an inhalation normally is performed while maintaining the most commonly used canister in a vertical direction with the stem pointing downwardly, and as this direction is the optimal direction with respect to the dosing of the next dose, it is desired that the canister is actually also released or de-compressed in this direction.